2-substituted-4,5-dicyanoimidazoles and their preparation from diaminomaleonitrile

ABSTRACT

DESCRIBED ARE 2-SUBSTITUTED-4,5-DICYANOIMIDAZOLES, E.G., 2-ETHOXY-4,5-DICYANOIMIDAZOLE, AND THEIR PREPARATION BY HEATING A COMPOUND III OF THE FORMULA   NC-C(-NH2)=C(-CN)-N=CH-Q-R   WHERE Q IS O OR S AND R IS HYDROCARBYL, IN AN OXIDIZING MEDIUM, E.G., A BENZOQUINONE. THE NEW COMPOUNDS ARE USEFUL AS BUFFERING AGENTS. COMPOUND III MAY BE PREPARAED, E.G., FROM DIAMINOMALEONTIRILE BY THE METHOD OF WOODWARD, U.S. PAT. 2,534331.

United States Patent Office Patented Dec. 11, 1973 ABSTRACT OF THEDISCLOSURE Described are 2-substituted-4,S-dicyanoimidazoles, e.g.,2-ethoxy-4,S-dicyanoimidazole, and their preparation by heating aCompound III of the formula NC NH:

where Q is O or S and R is hydrocarbyl, in an oxidizing medium, e.g., abenzoquinone. The new compounds are useful as buffering agents. Compound111 may be prepared, e.g., from diaminomaleonitrile by the method ofWoodward, US. Pat. 2,534,331.

BACKGROUND OF THE INVENTION (1) Field of the invention This invention isconcerned with a new class of substituted imidazoles, their use aschemical buffers and their preparation from diaminomaleouitrile.

(2) Prior art STATEMENT OF THE INVENTION It has now been discovered thatwhen diaminomaleonitrile(I) reacts with an orthoformate or atrithioorthoformate(II), the first (or intermediate) product formed isan a-hydrocarbyloxyoru-hydrocarbylthiomethyleneamino-fl-aminomaleonitrile of Formula 'III asshown in Equation A (Woodward) where Q may be or S, and R is hydrocarbylor substituted hydrocarbyl:

When a compound of Formula IH is heated under oxidizing conditions, thehydrocarbyloxy, hydrocarbylthio, substituted hydrocarbyloxy orsubstituted hydrocarbylthio group -Q--R is not lost but the productobtained is a 2-hydrocarbyloxy-, 2-hydrocarbylthio-, 2-substitutedhydrocarbyloxyor Z-substituted hydrocarbylthio- 4,5-dicyanoimidazole(IV)as shown in Equation B, in which Q and R are defined as above,

NC\ /NH1 NC\ o a C-Q-R H NC N=o- -R NC N 1!: (B) (III) (IV) In theformulas above, Q may be oxygen or sulfur and R is hydrocarbyl orsubstituted hydrocarbyl. All known hydrocarbyl groups are operable for Rin Formula IV. For example, R may be alkyl of 1-18 carbon atoms, alkenylof 3-18 carbon atoms, cycloalkyl (including bicycloalkyl andtricycloalkyl) of 3-18 carbon atoms, aryl of 6-18 carbon atoms,arylalkyl of 7-18 carbon atoms, alkaryl of 7-18 carbon atoms, alkaralkylof 8-18 carbon atoms.

Substituents on the hydrocarbyl groups in R may include halogen (F, Cl,Br or I), alkoxy of up to 18 carbon atoms, aryloxy of up to 18 carbonatoms, amino, lower alkylamino, di(loweralkyl)amino, carbonyl (e.g.,aldehyde or ketone functions), cyano or nitro. By loweralkyl is meant analkyl group of 6 carbon atoms or less. Preferably, there will be no morethan 3 such substitutents to any hydrocarbyl group R with no more than18 carbons in any substituent.

The hydrogen in Formula IV is acidic and is the source of the bufferingactivity against bases which is characteristic of all compounds ofFormula IV. When compounds of Formula IV react with bases such asmetals, metal oxides, and metal hydroxides, the corresponding metalsalts are formed as a result of the buffering action. These metal saltsin turn are useful as buifers against acids. The products of theinvention therefore include compounds of 'Formula V, where Q and R aredefined as above and M is hydrogen or one equivalent of a metal.

Nc\ /N NC N 14 By metal is meant any element of atomic number 3, 4,11-13, 19-32, 37-51, 55-84, and 87-103 and above. Alkali and alkalineearth metals are preferred.

The process of Equation A may be carried out neat, i.e., without anyadded reactants, solvents, diluents, or the like. However, for greatestconvenience, it is preferred to carry out the reaction in the presenceof an organic liquid which is chemically inert to the reactants andproducts. Preferably, the reaction medium is substantially free of water(i.e., less than 0.1%), is capable of dissolving the reactants and boilsat least 20 C. above the boiling point of the particular compound HQR,which is formed as a by-product in the process. Suitable liquids includeethers, such as anisole, phenetole, dibutyl ether and dioxane, nitrilessuch as propionitrile, butyronitrile and benzonitrile, esters such asethyl acetate, butyl acetate and diethyl succinate, and hydrocarbonssuch as toluene and xylene. Weights of reaction medium up to 25 and moretimes the weight of diamiuomaleonitrile may conveniently be used.

The molar proportions of diaminomaleonitrile and orthoforma-te which arebrought together to carry out the reaction of Equation A may be variedwidely, i.e., from 3 I 20:1 to 1:20, since any proportions used willyield at least some of the compound of Formula III. Equimolarproportions are preferred. The temperature for carrying out the reactionof Equation A may be in the range of -180 C. and is preferably in therange from 70-125 C. The temperature is preferably selected so that theby-product HQR can be removed by distillation. The distillation ispreferably continued until two equivalents of HQR have been collected,after which further heating is to be avoided.

The products of Formula III may be recovered from the reaction mixtureby known means such as evaporation, crystallization, distillation,chromatography, and the like, and may, if desired, be purified by suchmeans as recrystallization, sublimation, and the like. Alternatively,compounds of Formula III may be reacted further without isolation orpurification by adding an oxidizing agent directly to the reactionmixture from Equation A.

For the oxidative ring closure of Equation B, a wide variety ofinorganic and organic oxidizing agents may be employed. Thus, there maybe employed 2,3-dichloro-5,6- dicyanobenzoquinone, N-bromosuccinimide,N-bromophthalimide, N-bromourea, tetrabromoglycoluril and N-chlorosuccinimide and oxidants of similar oxidizing strength.

The reaction of Equation B may be carried out neat. Where the reactantsare solids, this may be accomplished by impact grinding as in a ballmill. Preferably, the reaction is carried out in the presence of anorganic liquid which is inert to the reactants and products, andparticularly one which is resistant to oxidation. Thus, there may beemployed nitriles such as acetonitrile and benzonitrile, esters such asethyl acetate and methyl propionate, ethers such as diethyl ether,tetrahydrofuran, dioxane, and the like, and hydrocarbons such as hexane,benzene, toluene, and the like.

The reaction of Equation B is preferably carried out in the temperaturerange between and +150 C. It is preferred to operate at the boilingpoint of the reaction meduim if one is employed.

The molecular proportion of oxidant to the compound of Formula III maybe varied widely, e.g., from 20:1 to 1:20, since any proportions willyield at least some of the imidazole product. For best results,approximately equimolar proportions are employed.

The 2-substituted-4,S-dicyanoimidazole product may be recovered from thereaction mixture by known means such as evaporation, crystallization,distillation, chromatography, and the like. When desired, the productmay be purified by known means such as recrystallization, sublimation,and the like. The product of Formula IV are colorless crystallinecompounds.

Compounds of Formula III in which the R group contains three or morecarbon atoms may be prepared by an alternative procedure in whichdiaminomaleonitrile is reacted with a mixture of a compound of FormulaII in which R contains one or two carbon atoms with an alcohol or thiolcontaining three or more carbon atoms. This can be shown in Equation C:

H; N 0 NH:

or up to twenty times as great an amount as the other tWO.

No added reactants are necessary for carrying out the reaction ofEquation C. However, yields are employed if a catalytic amount of anacid catalyst having a pKa of less than 2 is added. The amount of thecatalyst may vary from 0.001 to 1 equivalent per equivalent ofdiaminomaleom'trile and is preferably within the range of 0.01 to 0.1equivalent of acid per equivalent of diaminomaleonitrile. Suitable acidsinclude oxalic acid, toluene sulfonic acid, and trifiuoroacetic acid.

In the examples which follow, parts are by weight unless otherwiseindicated.

1 EXAMPLE 1 2-ethoxy-4,S-dicyanoimidazole Part A.-A solution of 20 g. ofdiaminomaleonitrile in 250 ml. of dioxane was heated in a 500-ml. flaskfitted with an addition funnel and a distilling column. The solvent wasallowed to distill slowly during one-half hour while 28 g. of ethylorthoformate was added, the distillation temperature being in the rangeof 90 C. during this time. Distillation was continued another half houruntil the stillhead temperature reached C. and about 150 ml. of liquidhad distilled. The reaction mixture was cooled to room temperature,diluted with 100 ml. of hexane, cooled to 0 C. and the precipitatedsolid removed by filtration. There was obtained 20.5 g. ofa-ethoxymethylenamino-B-aminomaleonitrile in the form of colorlesscrystals melting at 134-136" C.

Part B.A solution of 5.5 g. ofet-ethoxymethylenamino-'B-aminomaleonitrile and 6.4 g. of2,3-dichloro-5,6- dicyanobenzoquinone in 100 ml. of acetonitrile wasstirred and heated at reflux for 4 days. The reaction mixture was cooledand 20 g. of a neutral silica gel absorbent (Silicar CC-7) was added.Volatiles were stripped in a rotary evaporator. Elution with methylenechloride yielded a yellow solid. This was recrystallized from 200 ml. ofhot water to yield 3.0 g. of 2-cthoxy-4,5-dicyanoimidazole in the formof colorless crystals melting at 98-99 C. It was identified by its NMRand infrared absorption spectra.

Analysis.-Calcd. for C7H6N4O (percent): C, 51.9; H, 3.7; N, 34.6. Found(percent): C, 51.5; H, 3.8; N, 34.8.

IR (Nujol) 3.0, 3.7, 4.45, 6.1, 6.2, 6.8, 6.9, 7.2, 7.35, 7.6,

NMR (CDCl /TMS) 6:1.45, triplet, J =7, CH3; 8 388,

quartet, J=7, CH 6:103, broad singlet, NE.

UV (CHgCN) k =2660 nm. (e=11,550).

EXAMPLE 2 2-allyloxy-4,S-dicyanoimidazole P ait A.--To a slowlydistilling solution of 32.4 g. of diaminomaleonitrile in 250 g. ofdioxane was added dropwise 55.0 g. of triallyl orthoformate. Heating wascontinued until 200 ml. had been collected. The solution was cooled toroom temperature, and the precipitate which formed was collected byfiltration and recrystallized from a mixture ofether/tetnahydrofuran/petroleum ether to give 18.8 g. ofa-allyloxymethyleneamino-fi-aminomaleonitrile, M.P. C. The sampledarkened on standing.

IR (Nujol): 2.9, 3.0, 3.15, 4.45, 4.5, 6.1, 6.2, 8.0, 8.1,

NMR (CDCl /TMS): 6:8.01, singlet, CH; 6:6.0, broad, ==CH, 6:5.33,multiplet, =CH 8:4.67, doublet, 1 :5, CH =4.7, broad singlet, NH

Analysis.-Calcd. for C H N O (percent): C, 54.5; H, 4.6; N, 31.8. Found(percent): C, 54.2; H, 4.6; N,

Part B.A-solution of 8 g. ofa-allyloxymethylenamino-fl-aminomaleonitrile and 9 g. of2,3-dichlo-ro-5,6- dicyanobenzoquinone in ml. of acetonitrile wasrefluxed for 17 hours. The resulting solution was preadsorbed on 20 g.of a neutral silica gel absorbent (Sili-car CC-7) and chromatographed.Elution with methylene chloride gave a yellow solid which wasrecrystallized from 150 ml. of water to give 2.2 g. of colorless2-allyloxy-4,5- dicyanoimidazole, M.P. 95-.-97 C.

IR (Nujol): 3.1, 3.2, 4.43, 6.3, 6.48, 7.6, 7.8, 7.9, 8.8,

NMR (DMSO-d,;): 6:7.25, broad peak, (NH-|-H O); 6:6.13, multiplet, =CH;6:5.48, doublet J =18, multiplet J=1, =CH trans; 6:5.57, dou-blet i=8,multiplet J =1, =CH cis; 6:5.02, doublet J =6, CH

Analysis.-Calcd. for C H N O (percent): C, 55.2; H, 3.4; N, 32.2. Found(percent): C, 54.3; H, 3.4; N, 32.4.

EXAMPLE 3 2-methoxy-4,5 dicya.noimidazole Part A.-To a slowly distillingsolution of 32.4 g. of diaminomaleonitrile in 250 ml. of dioxane wasadded dropwise 31.7 g. of trimethyl orthoformate. Heating was continueduntil 20 ml. of distillate had been collected. The precipitate whichformed in the reaction mixture on cooling was recrystallized fromtetrahydrofuran/pentane to yield 29 g. ofa-methoxymethyleneamino-p-aminomaleonitrile in the form of colorlesscrystals melting at 134 C.

Part B.A solution of 4.0 g. of u-methoxymethylamino-fl-aminomaleonitrileand 5.1 g. of 2,3-dichloro-5,6-dicyanobenzoquinone in 150 ml. ofacetonitrile was heated at reflux for one day. About 20 g. of a neutralsilica gel absorbent (Silicar CC-7) was added and volatiles werestripped in a rotary evaporator. Elution with methylene chloride gave0.9 g. of a yellow solid. This was recrystallized from hot water toyield 2-methoxy-4,5-dicyanoimidazole in the form of colorless crystalsmelting at EXAMPLE 4 2-cyclohexyloxy-4,S-dicyanoimidazole Part A.-Into a500-ml. 3-neck flask equipped with magnetic stirrer, addition funnel anddistilling head was placed 16.8 g. diaminomaleonitrile (0.15 mol), 25 g.of cyclohexanol (0.25 mol) and 125 ml. of dioxane. The flask was heatedto slowly distill the dioxane while 22.2 g. of triethyl orthoformate(0.15 mol) was added dropwise over a period of 3 hours. After 100 ml.had distilled, the reaction mixture was cooled and preadsorbed on 20 g.of a synthetic magnesia silica gel absorbent Florosil) Elution withbenzene gave an oil which slowly crystallized to give 7 g. ofa-cyclohexyloxymethylenamino-flaminomaleonitrile. The infrared spectrumshowed bands at 2.9, 3.0, 3.2, 3.4, 3.5, 4.45, 4.5, 6.1, 6.2, 6.9, 7.35,7.9, 9.4, 10.35, 11.254p. The NMR spectrum (CDCl /TMS) showedabsorptions for the cyclohexyl protons between 8:1 and 2.2, the methyneproton at 6:4.7 and the =CH at 6:8.0.

Part B.A solution of 6.6 g. ofa-cyclohexyloxymethylenamino-B-aminomaleonitrile and 5.7 g. of2,3-dichloro- 5,6dicyanobenzoquinone in 250 ml. of acetonitrile washeated at reflux for about 18 hours. It was preadsorbed on g. of asynthetic magnesia silica be] (Florosil) and eluted with cholorform toobtain 3.0 g. of crystalline 1-cyclohexyloxy-4,S-dicyanoimidazolemelting at 155-155.5 C. after recrystallization from ethanol-water.

IR (Nuiol), band at 3.13.8p.; peaks at 3.75, 4.5, 6.3, 6.5,

NMR (CDCl /TMS) 6=1.1-2.2, broad singlet; 6:5.0,

very broad; 6:6.6.

EXAMPLE 5 2-dodecyloxy-4,S-dicyanoimidazole Part A.-In the generalprocedure of Example 4, Part A, 10.6 g. of trimethyl orthoformate wasslowly added to a gently distilling solution of 10.8 g. ofdiaminomaleonitrile, 18.6 g. of dodecanol and 1 g. of oxalic acid in 150ml. of dioxane. The reaction product was chromatographed on a syntheticmagnesia silica gel (Florosil). Elution with benzene and methylenechloride yielded 6.0 g. of a-dodecyloxymethylenamino-p-aminomaleonitrilein the form of colorless crystals melting at 109-1l0 C.

Part B.A solution of 2 g. ofoz-dodecyloxymethylenamino-p-aminomaleonitrile and 1.3 g. of2,3-dichloro-5,6- dicyanobenzoquinone in 50 ml. of acetonitrile washeated at reflux for two days. The reaction mixture was cooled to roomtemperature and absorbed on 5 g. of a synthetic magnesia silica gel(Florosil) Elution with benzene gave 1.0 g. of2dodecyloxy-4,S-dicyanoimidazole as colorless crystals, M.P. 45 C. Theinfrared spectrum showed bands at 3.1, 3.4, 3.5, 4.4, 6.3, 6.5, 6.8,6.9, 7.3, 7.6, 9.4 and lO.4p-.

NMR (CDCl /TMS). 8:0.9, triplet, I =7, CH 6:1.28,

singlet CH 6:4.45, triplet, J'=6.5, OCH

EXAMPLE 6 2-undecylenyloxy-4,5-dicyanoimidazole Part A.--In the generalprocedure of Example 4, Part A, 22.2 g. of triethyl orthoformate wasadded to a gently distilling solution of 16.2 g. of diaminomaleonitrile,25.2 g. of w-undecylenyl alcohol and 1.0 g. of oxalic acid in 250 ml. ofdioxane. The reaction product was chromatographed on a syntheticmagnesia silica gel ('Florosil). Elution with benzene yielded 7.8 g. ofa-undecenyloxymethylenamino-fl-aminomaleonitrile in the form ofcolorless crystals, M.P. C.

Part B.A solution of 5.7 g. ofa-undecenyloxymethylenamino-p-aminomaleonitrile and 3.8 g. of2,3-dichloro- 5,6-dicyanohenzoquinone in 200 ml. of acetonitrile washeated at reflux for 1 day. The reaction mixture was cooled to roomtemperature and absorbed on 10 g. of a synthetic magnesia silica gel(Florosil). Elution with benzene gave 1 g. of2-undecenyloxy-4,S-dicyanoimidazole in the form of a yellow oil. Theinfrared spectrum showed bands at 3.1, 3.3, 3.45, 3.55, 3.8, 4.5, 6.1,6.3, 6.5, 6.8, 6.95, 7.3, 7.65, 8.8, 9.4, 10.0, 10.4, 10.9, 12.3, 13.1,13.2 and 14.2n.

NMR (CDCl /TMS): 6:1.33, singlet CH 6:2.12, broad, OCH2CH2-; 6:4.47,triplet I=6, 001-1 6=4.85-5.15 AB of ABX, vinyl: 6:5.68, X of ABX,

vinyl; 6:6.44 NH.

EXAMPLE 7 2-benzyloxy-4,5dicyanoimidazole Part A.--In the generalprocedure of Example 4, Part A, 23 g. of triethyl orthoformate was addedto a gently distilling solution of 16.2 g. of diaminomaleonitrile, 16.2g. of henzyl alcohol and 1.2 g. of oxalic acid in 250 ml. of dioxane.The reaction product was chromatographed on a synthetic magnesia silicagel (Florosil). Elution with benzene yielded 8.2 g. ofa-benzyloxymethylenamino-fl aminomaleonitrile in the form of colorlesscrystals, MP 141 C.

Part B.A solution of 8 g. ofa-benzyloxymethyleuamino-B-aminomaleonitrile and 7 g. of2,3-dichloro-5,6- dicyanobenzoquinone in ml. of acetonitrile was heatedat reflux for 2 days. The reaction mixture was cooled to roomtemperature and absorbed on 10 g. of a synthetic magnesia silica gel(Florosil). Elution with methylene chloride gave 1 g. of2-benzyloxy-4,5-dicyanoimidazole in the form of a light colored crystal,melting at 162--163 C.

The infrared spectrum showed bands at 3.1, 3.2, 4.45, 6.2, 6.3, 6.5,7.6, 9.35, 10.55, and 13.45

NMR (CDCl /TMS): 6:5.39, singlet OCH 5=7.38,

singlet C H EXAMPLE 8 Sodium salt of 2-ethoxy-4,5-dicyanoimidazole To 2g. of 2-ethoxy-4,S-dicyanoimidazole in 5 ml. of water was added withstirring 1.05 g. of sodium bicarbon- 7 ate in 15 ml. of water. A gas wasevolved. The solution was stirred at room temperature for 17 hours,treated with decolorizing charcoal (Darco), and the water removed on arotary evaporator. The residue was dissolved in tetrahydrofuran and thesolvent again removed giving 2.2 g. of the sodium salt of2-ethoxy-4,5-dicyanoimidazole, MP 275 C. The infrared spectrum showedbands at 4.45, 6.6, 7.05, 7.4, 7.6, 8.8, 9.2, 9.3, 9.7, 9.8, 10.9, 13.0and 13.2.

EXAMPLE 9 A solution of 4.1 g. ofa-ethoxymethylenamino-p-aminomaleonitrile and 4.5 g. ofN-bromosuccinimide in 100 ml. of acetonitrile was heated at reflux for 2hours. The solution was pre-adsorbed on a synthetic magnesia silica gel(.Florosil). Elution with methylene chloride gave 2-ethoxy-4,5-dicyanoimidazole which was identical with the product ofExample 1, Part B.

' All of the compounds of Formula V are. useful as chemical buffers inalcohol/water systems. This is illustrated as follows:

EXAMPLE A 2-ethoxy-4,S-dicyanoimidazole (0.5 g.) was dissolved in amixture of 25 ml. of methanol and 25 ml. of water. The pH was observedby a pH meter (Corning, Model 7) to be 3.1. The solution was thentitrated with 0.1 N sodium hydroxide with the following results:

Base added (ml.): pH 3.1 1 3.5 3 3.9 5 4.1 7 4.3 11 4.6 15 4.9 5.3 6.026 6.7

The solution (containing the ionized l-sodio salt of2-ethoxy-4,5-dicyanoimidazole) was then back-titrated with 0.1 Nhydrochloric acid with the following results:

Acid added (ml.) pH 1.5 6.5 6.5 55 11.5 49 16.5 46 21.5 4.2 26.5 3.531.5 2.7

This shows that 2-ethoxy-4,S-dicyanoimidazole is a useful buffer foracids and bases in the pH range 3-5. In contrast, a mixture of 25 ml. ofmethanol and 25 ml. of water showed no bufiering action when titratedwith 0.1 N sodium hydroxide and back-titrated with 0.1 N hydrochloricacid as follows:

Base added (ml.): pH 7.8

Acid added (ml.):

maul-bun When lithium, potassium, rubidium and strontium hydroxides areemployed in place of sodium hydroxide, the corresponding lithium,potassium, rubidium and strontium salts of 2-ethoxy-4,S-dicyanoimidazoleare obtained. Other metal salts are prepared from these by metathesis.

When the orthoformates and trithioorthoformates shown in Table I beloware substituted for triethyl orthoformate in the procedure of Example 1or for triallyl orthoformate in the procedure of Example 2, the indicated 2-substituted-4,5-dicyanoimidazoles are obtained.

TABLE I Product Item Orthoformate (4,5-dicyanoimidazole) 1 Triisopropyl2-isopropyloxy- 2.- Triisobutyl Z-isobutyloxy- 3... Trieyelohexyl2-cyclohexyloxy- 4-- Tn'(2-ethylhexyl) 2-(2-ethylhexyloxy) 5 n'octylZ-octyloxy- 6-. TribenzyL- 2-benzyloxy- 7 Trimesityl- 2-mesityloxy- Trihenyl Z-phenoxy- Tn'(2-naphthyl). 2-(2-naphthoxy)- Tn yl) 2-(o-tolyl)-Tri(tribromophenyl) 2-tn'bromophenoxy- 12 Tri(o-nitrophenyl)--2-(o-nitrophenoxy)- 'Irithioorthoformate Z-methylthio- 2-butylthi0-2-phenylthio- Z-benzylthio- 2-(a-naphthylthio)- 2-(p-ehlorophenylthio)-When the alcohols and thiols shown in Table II below are substituted forcyclohexanol in the procedure of Example 4 or for dodecanol in theprocedure of Example 5, the indicated2-substituted-4,5-dicyanoimidazoles are obtained.

TABLE II Item Alcohol or thiol Product (4,5-dicyanoimidazole) 16,6,6-trifluorohexanol 2-(6.6.6-trifiuorohesylosy) 210,11dibromoundeeanol 2-(10.11-dibromoundeeyloxy)- 3 IO-bromoundeeanol2-(10-bromoundecyl0xy)- 4.- 10,11-dieh1oroundecanol2-(10.11-dich10r0undeoyloxy)- 3.- 10-chloroundeeanol.2-(10-chlor0undecyloxy)- 2-(10-iodoundecyloxy)- 10-iodoundecanolfi-cyanohexanoh.

arts, I propose to be bound solely by the appended claims. Theembodiment of the invention in which an exclusive property or privilegeis claimed are defined as follows:

1. A compoud of the formula Q is O or S;

M is hydrogen or alkali or alkaline earth metal; and

R is: alkyl of 1-18 carbon atoms; alkyl of 1-18 carbon atoms mono-, diortri-substituted with halogen or lower alkoxy or mono-substituted withcyano, nitro, amino, di(loweralkyl)amino or phenoxy; alkenyl of 3-18carbon atoms; cyclohexyl; or phenyl.

2. The compound of claim 1 named 2-ethoxy-4,5-dicyanoimidazole.

3. The compound of claim 1 named 2-a1ly10xy-4,5-dicyanoirnidazole.

4. The compound of claim I named 2-methoxy-4,5-dicyanoimidazole.

5. The compound of claim 1 named 2-cyclohexy1oxy- 4,5-dicyanoimidazole.

6. The compound of claim 1 named 2-dodecyloxy-4,5- dicyanoimidazole.

7. The compound of claim I named 2-undecylenyloxy- 4,5-dicyanoimidazole.

8. The compound of claim 1 named 2-benzyloxy-4,5- dicyanoimidazole.

9. The compound of claim 1 named the sodium salt of2-ethoxy-4,S-dicyanoimidazole.

10. The process of preparing a compound of claim 1 in which M is H whichcomprises heating a p-aminomaleonitrile of the formula N NH:

wherein Q and R are as in claim 1, at a temperature in the range 20 to+150 C., in the presence of an oxidizing agent of the group consistingof 2,3-dich1oro-5,6-dicyanobenzoquinone and N -bromosuccinimide.

11. The process of claim 10 wherein the B-aminom-aleonit-rile isa-allyloxymethyleneamino-fl-aminomaleotrile.

12. The process of claim 10 wherein the fl-aminomaleonitrile isu-allyloxymethyleneamino-p-aminomaleonitrile.

13. The process of claim 10 wherein the fl-arninomaleonitrile isu-methoxymethylenearnino-p-aminomaleonitrile.

14. The process of claim 10 wherein the fl-aminomaleonitrile isa-cyclohexyloxymethyleneamino-B-arninomaleonitrile.

15. The process of claim 10 wherein the B-aminomaleonitrile isa-dodecyloxymethyleneamino-fl-aminomaleonitrile.

References Cited UNITED STATES PATENTS 2,534,331 12/ 1950 Woodward260309 OTHER REFERENCES Cook et -al., Chem. Abst., v01 44, columns3907-8 (1950). QD1.A51.

Yamada et al., Chem Abst., vol. 72, N0. 43734w (1970). QDLASI.

Yamada et al., Chem. Abst, vol 74, No. l25693n (1971). QDLASI.

NATALIE TROUSOF, Primary Examiner US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE 0F QUECTIGN Patent: No.3,778,}4-46 Dated December 11, 1973 Inventofls) Frank J. Weigert It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

I I n Y] Col. 2?, line 3 top atom in ring of Iormula IV should be "InCol. '5, line 50 correct spelling of "products" Col. line 2 changeemployed to "improved% "20" should be "200".

Col. 5, line 19 C01. 5, line 51 "11.25 4 should be "1125".

Col. 8, line 3 correct spelling; of "trifluorohexylox-y".

Col. 8, line i icorrect spelling", of nitrohexyloxy.

C010 8, line 46 correct spelling of "B-methoxy [B-ethoxi] ethoxyy' Col.8, line 64 insert wherein",

Col. 10, line 2, claim 11 "on-allyloxymethylcneamino" should be"on-ethoxymethyleneamino"o Signed. arid sealed this 9th day of April1971 (ssAL) fittest:

hmJARD i-I.FLJ-JTOI U1;R,JH. G. MARSHALL DAMN Acts-sting Ufficer'Commissioner of Patents mg UNITED STATES PATENT OFFICE CERTIFICATE OFCORRECTION Patent No. 3 178, 6 Dated December 11, 197} Inventor(s) F nkJ. Weigert It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

F l Col. 2, line 3 top atom in ring of formula. IV should be "N". Col.3, line 50 correct spelling of "products" Col. line 2 change employed to"improved",

Col. 5; line 19 "20" should be 20c)".

Col. 5, line 5r- "11.25 4-" should be "11,25".

Col. 8, line 3 9 1-- correct spelling of "triflfiorohexyloxy".

Col. 8, line l icorrect spelling, o I nitrohez-zyloxy.

C01. 8, line 46 correct spelling of "B-methoxy fp-ethoxi] ethoxfi' Col.8, line 6 L insert wherein".

Col. 10, line 2, claim 11 "oz-allyloxymethyleneamino" should be"on-ethoxymethy-leneamino".

Signed and sealed this 9th day of April 197b,.

(SEAL) Attest:

I LD IJARD L'LFLETOEEHJR. G; MARSHALL DAMN Attesting OfficerCommissioner of Patents

